Is there supposed to be no baffle venting in an ortho phone? I noticed the Fostex T40 has a solid baffle design, and the Yamaha's don't even really have a baffle to speak off (seems that the driver is about as big as the housing).

Baffle vents are something AKG dreamed up to replace the passive diaphragms in designs like the K240 Sextett. Near as I can figure, it was an attempt to tweak the frequency response of the phone and give a more open spatial presentation. Normally, venting the baffle would be anathema-- you don't want bass backwave leaking into the earcup for fear of bass cancellation.

Considering that a typical ortho/iso driver is basically a tweeter, you want to retain all the bass you can. Thus the shallow earpads, etc. The Fostex type driver has more excursion capability and thus doesn't need the restricted earcup volume and shallow pads, but it uses them and then tunes the diaphragm higher to make damping less of a problem. Thus a big driver in phones like the T30 and T50 can be lightly damped and have an open back and still have clean, clear (but not jaw-dropping) bass. It's all a bunch of tradeoffs. Carefully study the volume of air contained in a YH-100 earpad and compare it to the various dynamic 'phones we've been using.

Quote:

Originally Posted by AudioCats

Also, since the damping material is right on the back of the driver to slow down the air coming in/out, does housing style (open/closed) still make a difference?

Yes, to a certain extent. A totally open driver+earcup+earpad combination (think Senn HD 414) will have max soundstage, of course.

Quote:

Originally Posted by AudioCats

I got a pair of SFI ortho mid-range coming, but they are way too big (3"x3" square) to put in the QP housings......Kind of forcing me to woody the Accura's for them.

Normally venting the baffle would be anathema-- you don't want bass backwave leaking into the earcup for fear of bass cancellation..

Thanks Wualta. so whether the QP55x or 45x baffle doesn't make any differences then, the vent needs to be sealed anyway, am I right? Then the 45x seems to be a better choice because of the (smaller) pleather pads...

Quote:

Originally Posted by wualta

The Fostex type driver has more excursion capability and thus doesn't need the restricted earcup volume and shallow pads.....Carefully study the volume of air contained in a YH-100 earpad and compare it to the various dynamic 'phones we've been using..

Does this mean the YH-1/100 still don't really have a large enough diaphragm to be used in a circumaural design? wow
No wonder you didn't want to put them SFI tweeters into the QP housing, they are even smaller....

Quote:

Originally Posted by wualta

Wow, you got a pair of the old Sawafuji Dynapleat drivers? Cool.

I hope they will have enough treble.... When I bid I only thought about the bass, and forgot the mid-ranges have thicker diaphragm so they might not go as high.....

Does this mean the YH-1/100 still don't really have a large enough diaphragm to be used in a circumaural design?

No, but it means the housing should be designed for the ortho driver or moddified to work well with it.
I really like the L3000 pads on my Donuts too, because they're somewhat like the pads wualta has. Almost a cross between circumaural and supraaural, with a smaller opening in the center.

hmmm, I think I have just the pads for the job. very flat pleather circumaural pads from some old crappy cans I broke a while ago. giving them a try. I'd still like to use the stock pads though so I might just seal the baffle.

Baffle vents are something AKG dreamed up to replace the passive diaphragms in designs like the K240 Sextett. Near as I can figure, it was an attempt to tweak the frequency response of the phone and give a more open spatial presentation. Normally venting the baffle would be anathema-- you don't want bass backwave leaking into the earcup for fear of bass cancellation.

AKG likely was the first to think it up - resulting in the K241 headphone, which became the K240-M -- and i have this early form of the K240-M -- but the rest of the dynamic headphone industry seems to use it too.

Upper-end sennheisers have tuned filtered vents like a K501, and all the upper-end beyers I've seen have an open-frame baffle that is covered on both sides with nonwoven fabric - including (and likely starting with) the seminal 1980 DT880-S.

I didn't know Beyer was on the bandwagon too. I'll have to take a look at the HD600, if I can pry them loose from my son.

I bought the QP-45x because it was cheapish and promised to be comfy, and to see what I could do with it, but it occurs to me now that an old busted electret 'phone like the Stax SR-30 or 40 or the A-T ATH-6/7/8, being made for a driver with limited excursion, would make a good fosterfone for ortho/iso drivers. Come to think of it, I find my ATH-70 to be a real washout, SQwise... Maybe I could try the HP-1 drivers in that... light, comfy, compact. Hmm.

And yes, if I were using the QPs to host "pinch" type ortho drivers, I'd seal the baffle, preferably with something semirigid and inert, like yello-tak.

When you're conserving bass, seals become important. Make sure that not the slightest opening exists that could make a pathway for bass backwave to get close to your ear except via the open back.

The only reason I didn't put the SFI drivers in the QP was that they're just too dang small in diameter. It would be a pain to try to seal them into the big 57mm cavity. They do have the advantage of not having any factory damping, so they really should go into an open-back headset.

No extra baffle seal/damping: Good sound, bit bass shy for a basshead like me but it has great mids and highs and soundstage is nice.

Half of the vents sealed all the way around: no bass, tinny sound

Full vent sealing: Good sound of a different sort, has substantially increased bass but the soundstage closes a little. The sound is very full bodied so it is good for more than just certain instruments and voice.

YH-100s in QP55x and damping

Stock QP55x damping: tinny sound

Just the foam from the QP55x: much better, balances out the sound and opens the soundstage

Interesting results! What exactly is "stock QP55x damping" as it relates to the YH-100 drivers?

Stock QP damping is the foam along with that self adhesive felt pad. The pad was so dense that it was actually deflecting the backwave into the earcup instead of just damping it.

Funny thing, I keep balancing out the sound towards highs and mids. First I did the transplant which opened up the cans a lot. Then I changed to flatter pads for better bass. Then I sealed the baffle with blu-tak completely for even more bass. Now I changed the pads back and I'm almost back to where I started. hahaha

Oo! Glad to hear the felt (I assume it's in the form of a damping disc on the back of the driver) did some good! Did it trade off some soundstage, though?

Quote:

Originally Posted by FooTemps

Stock QP damping is the foam along with that self adhesive felt pad. The pad was so dense that it was actually deflecting the backwave into the earcup instead of just damping it.

Yep, a damping pad does have "reflex" properties. Make it dense enough and it raises the natural resonant frequency of the diaphragm plus relects sound, and you've suddenly got way too much treble. The YH-100 driver can be damped more than the other commonly-available Ortho drivers, but not a whole lot more.

I don't have a 55, so forgive all the "whuzzat?" questions.

Quote:

Originally Posted by FooTemps

Funny thing, I keep balancing out the sound towards highs and mids. First I did the transplant which opened up the cans a lot. Then I changed to flatter pads for better bass. Then I sealed the baffle with blu-tak completely for even more bass. Now I changed the pads back and I'm almost back to where I started. hahaha

Fun, isn't it!

Be sure to take some pictures, or draw us a diagram.

How's the extreme high treble? Would an AKG fanatic be satisfied?

Got any earpads that cover the entire baffle except for the driver, like the pads on the T50/Maior?

Our local Menards hardware store has a box of fiberglass insulation remnants for cheap. We've experimented with damping and reflections; time for a few experiments with absorption.

Ok, got my SFI planar midrange in mail. From what I can see, they are not exactly ortho, they are just modified dynamics. each driver uses 5 oblong voice coils, each voice coil is around a bar shape magnet. One piece square diaphragm, with little domes where the voice coil is ( like 5 oblong dome tweeters with diaphragm connecting together). I don't think it will have the 'rigid disc' effect of a true othor diaphragm.

Sorry I don't have any pictures, it is basically impossible to take out the front grill without distroying it. These drivers also have a paper sealing tube all the way around back side (sealing the back waves?) so opening the real panel doesn't show the guts either, unless, well, if you distroy the paper....